Electric steam iron



April 28, 1959 w. w. RAUSE ETAL 2,883,779

ELECTRIC STEAMIRON Filed Jan. 12, 1955 uvvE/v TORS,

WALTER W KRAUSE, ALFRED E. SCHWANEKE United States Patent ELECTRIC STEAM IRON Walter W. Krause, Chicago, and Alfred E. Schwaneke, Northbroolr, 11]., assignors to Dormeyer Corporation, Chicago, 11]., a corporation of Illinois Application January 12, 1955, Serial No. 481,367

9 Claims. (Cl. 38-77) The present invention relates to thermostatically actuated indicators and more particularly to devices of this character for indicating the water level inside an electrically powered steam iron.

One of the problems of previous irons of this type has been the existing difficulty for the operator to determine the quantity of water remaining in the iron tank, and to know when this quantity has diminished to the point where replenishment is necessary. Users of previous irons of this type frequently have had to use a trial and error method wherein either too frequently or too infrequently the water supply was replenished. This resulted in either a waste of time spent in too many refilling operations on a small quantity basis to be sure to have a continuous supply of steam or, more seriously, in running dry repeatedly and scorching the fabric each time due to the higher temperature at which the iron is set for steam ironing.

Previous attempts at a solution to the problem have proven unsatisfactory. For example, a float and linkage mechanism has been utilized, but as the iron is moved, the water sloshes around and moves the float incessantly, thus preventing an accurate indication of the water level during movement of the iron. This is also accompanied by an annoying rattling of the float mechanism.

Another fluid level indicator utilizes a mercury column thermostat provided with spaced contacts, one of which represents the normal functional setting of the thermostat, and the other the maximum allowable temperature of the fluid. This is, however, too complex and is felt to be too expensive a device to install in an iron to be offered for sale to the average economy-minded housewife.

One of the principal objects of this invention is, therefore, to provide a simple, inexpensive and accurate indicator of a low water level inside an electrically powered steam iron.

Another object is to provide a silent and stable means for giving warning when it is time to refill a steam iron for assured continuous supply of steam.

A further object is to provide means for accomplishing this desired result by utilization of the electric power of the iron.

The invention is also characterized by thermostatic elements which, when cooled by the heat conductive action of water inside the tank of the iron, will not be actuated; but when the water level inside the iron has receded to a predetermined limit, the water will be held forward of the thermostat by a battle and no longer will conduct heat away from the thermostatic elements, and such elements will deflect and contact each other and thus close an electric circuit which activates an indicator light located in an eye-catching position on the outside of the iron.

These being among the objects of the invention, other and further objects will be apparent from the drawings and the description relating thereto.

2,883,779 Patented Apr. 28, 1959 In the drawings:

Fig. 1 is a vertical sectional view taken longitudinally through a steam iron embodying the invention;

Fig. 2 is an electrical schematic diagram showing the electrical relationship of the invention to the other elements in the circuit of the steam iron, and

Fig. 3 is a plan view of the floor of the water tank taken at approximately the critical level of the water.

In general, the iron embodying this invention comprises a sole plate 10, a finishing housing 11 having a floor 12 forming therewith a tank 62, a handle 13 having a valve construction 14 at the front end, a manual heat control dial 15 below the grip 16 of the handle 13, and an extension cord 17 by which the electricity is supplied to the heater components of the iron extending preferably vertically through the rear end of the handle.

More particularly, the sole plate 10 is made up of essentially four units, the bottom member 20 of high heat conductive metal, the heater-carrying member 21, also of high heat conductive metal defining steam generating chamber 39, the cover 22 of low heat conductive metal covering the generating chamber 39, and the heat control thermostat indicated generally at 23 to the rear of the chamber 39.

From its margin, which follows the contour of the lower member 20, the housing 11 comprises a stainless steel shell 60 which arches upwardly to any desired design shape so that sufficient space is contained therein for the storage of a substantial amount of water for steam generation. The water is supported in a depending floor defining bottom portion 12, whose marginal edges are welded to the shell as at 61 where the marginal edges engage the finishing shell 60 to provide the tank 62. Thus the tank is located above the chamber 39, and, immediately above the chamber 39 the bottom wall of the tank 12 is depressed as at 63 to provide a low point in the tank. A bafile is provided at the rear of the depressed portion 63. This battle acts to retain water in the forward end of the tank when this water has been depleted to the extent that its level in the tank is below the upper edge 127 of the bafile. This serves to isolate a small reserve supply of water when the level is dangerously low by confining it to the depressed portion 63 even when the iron is upended momentarily while in use. The slot and shape of the baflie encourages water to enter the depressed portion while the iron is in use and discourages escape of the reserve supply from the depression.

The preferred embodiment also includes, immediately above the heat control thermostat 23, a heat-actuated thermostatic assembly comprising two blades 126 and 12S bearing contacts 129 on their free ends. The upper blade 126 is a bimetallic one mounted in intimate heat exchange relationship with the bottom wall of the tank 12 by the assembly of dielectric washers and rivet 130. The two blades are, thereby, electrically insulated from each other at their fixed ends.

Viewing Fig. 2, it is seen that the blades bearing the contacts 129 are in series with a glow lamp 131, and in parallel with the main circuit of the iron heater 35, thus utilizing a portion of the line current from leads 17. Glow lamp 131 is also shown in Fig. 1 on the forward edge of the case 60 where the bulb of the lamp can be exposed as shown or mounted behind a ruby window.

In operation, when water is in the tank 62 in plenitude, the water is above the level shown in Fig. 1 as at 132. Under these circumstances the water will conduct heat away from the bimetal 126 and its mounting that is radiated to it from the heat that is generated by the heating element 21. The heat dissipated in the water will be in sufiicient amounts to maintain the bimetallic strip 126 deflected away from the other blade so that no contact is made between contact points 129 on the free ends of blades. No closed circuit is made and the light 131 will not glow as long as'water is in contact with the floor of the tank above-the bimetallic blade 126. H When, however, the water had been depleted by steam production to the extent that it falls to approximately the level indicated by the water level line 133 in front of the bafile with all the water propelled thereto by the motion of the iron as used, the baffle 125 will prevent water that has been thrown -forward by the movement of the iron by the user from running back torthe rear of the tank 135. V

Thus, when the water level is as at 133, there is no water above the bimetallic "strip 126 to conduct heat away from the bimetallic strip 126, and as a result, the

temperature will rise in that area due to heat transmitted to the blade 126 from the heating coil 35. Thereupon the bimetallic blade 126 will bend downwards towards the lower blade 128, the two contacts 129 will close, thereby lighting the bulb 131 and indicating to the operator that the water level has reached the point Where replenishment is necessary.

It will be noted that the water level indicating thermostatic combination 134 is located in an entirely different circuit from that of the heat control thermostat 23 and operates independently of thermostat 23. Further, the indicator 134 lies in a circuit with the light bulb 131 that is in parallel relationship, electrically speaking, with the main switch circuit of the iron. The heat activating the water level indicating thermostat 134 comes to it indirectly from the heating element 35, while the heat control thermostat is activated by heat transmitted to it directly from the sole plate 29, and indicates the temperature of the ironing surface. Further, the water level indicator is not utilized as a heat indicator, but utilizes a preset critical heat point to indicate the proper replenishment point of the tank water, preferably a setting to close at approximately 212F.

To avoid extensive description, several details of construction shown of the electrically powered steam iron were omitted. Any questions regarding this construction may be clarified by referring to application Serial No. 425,814, reference to which is hereby made.

Consequently, it will be seen from the description of the invention and the discussion of its principles of opera- "tion that various and further modifications can be made to'accomplish the objects enumerated without departing from the spirit of the invention, the scope of which is commensurate with the appended claims.

What is claimed is: 1. An electric'steam iron comprising a steam generating chamber, a heater in heat exchange relationship therewith, a'tank above said heater with a bottom wall defining two levels receiving heat from said heater, a thermostatic switch in heat exchange relationship with the bottom wall at the upper level actuated at tempera tures above the boiling point of water, the said switch being connected in an electric circuit with a glow lamp.

2. In an electric steam iron of the type described, including'a heated sole plate having a vaporizing chamher for generating steam in said iron, a water tank with a bottom wall above the sole plate, said bottom wall having a depression therein connected to said vaporizing chamber, the rear of said depression sloping upwardly and backwardly to the main portion of said bottom'wall,

an upwardly and forwardly extending bathe located on said bottom wall adjacent said backwardly and upwardly sloping portion of said depression for retaining water in said depression, and'thermo-responsive means operative at the boiling of water disposed in heat exchange rela- "tion ship with said'sole plate and the "main portion of said bottom Wall.

3. An electric steam iron comprising an electrically heated sole plate, a water tank with a bottom wall above said sole plate, one portion of said bottom wall having a depression therein with a portion of the bottom wall at the rear of said depression sloping backwardly and upwardly to meet the main portion of said bottom wall, an upwardly and forwardly extending baflie on said bottom wall portion adjacent said sloping portion to retard the flow of water from the depression to the rest of the tank, thermostatic means disposed in good heat exchange relationship with the main portion of the bottom wall of the tank, and indicator means actuated by said thermostatic means at a temperature above the boiling point of the water.

4. An electric steam iron comprising a cover, an electrically heated sole plate closing the bottom of said cover and having a water vaporizing chamber, a water tank within said cover and having a multiple level bottom wall'above 'said'sole plate, a lower one of which levels defines'a depression to establisha low point in the tank connected to said vaporizing chamber for' supplying water thereto, the rear of said depressionsloping backwardly and upwardly to meet an upper level of said bottom wall, an upwardly and forwardly extending bafile member on said bottom wall adjacent said upwardly and backwardly sloping portion of said depression to retard flow of water from the depression to the upper level during manual use of said iron, an electric switch circuit connected to an electric supply source, a thermo responsive switch disposed in heat exchange relationship with the bottom wall at its upper level rearwardly of said baffle, and a warning indicator circuit controlled by said switch, said switch actuating said circuit while the temperature of the upper level of the bottom wall is above the temperature of the bottom wall at said depression, said cover shielding said bottom wall levels from ambient atmosphere.

5. An electric steam iron comprising "an electrically heated sole plate having a water vaporizing chamber, a water tank above said sole plate having a bottom wall receiving heat from said sole plate and defining two levels the lower of which comprises a depression connected to said vaporizing chamber to supply water thereto, a baflie member between said levels to retard free flow of water between said levels during manual use of the iron, thermostatic means between said bottom wall and sole plate in heat exchange contact with the bottom wall at the upper of said two levels, an electric indicator circuit including a lamp, said thermostatic means actuating said indicator circuit at a temperature above the temperature of water confined in said depression.

6. The combination described in claim S'Wherein the water in the tank above the upper of said two levels absorbs through said bottom wall heat received by said thermostatic means from said sole plate while a substantial supply of Water is in said tank above said upper of said two levels.

7. A steam iron comprising an electrically heated sole plate having a water vaporizing chamber therein, a tank for storing water having two levels, the lower level of said tank being positioned immediately above the said sole plate and connected to said chamber to supply water thereto, the upper level of the tank being provided with a lower wall, thermostat means located between said lower wall of the upper level of the said tank and the sole plate responsive to heat radiated from said sole plate and disposed in heat exchange contact with the said lower wall, said lower wall conducting heat fromsaid thermostat means to water present in said upper tank level above the level of the point of said heat exchange contact, and indicating means actuated by said thermostat means'when the level of water in said tank is below said point and the temperature of said wall 'at' said point rises above a predetermined temperature.

comprising a vaporizing chamber, heating means juxtaposed to the chamber, a tank having an upper level and a lower level, the upper level being provided with a lower wall in spaced relationship with the heating means, the lower level of said tank being connected to the vaporizing chamber for supplying liquid to said chamber, the lower wall of the upper level of said tank receiving heat radiated from the heating means, thermostatic means disradiated from the heating means, thermostatic means disposed in heat exchange contactwith said lower wall of the upper tank level and indicator means actuated by said thermostat means at temperatures above the boiling point of said liquid, whereby said thermostat means is held at a temperature below the boiling point of the liquid during those periods liquid is present in the upper tank level, and may be raised to above the boiling point of the liquid in the absence of liquid in the upper tank level.

9. In a steam iron having an electric heater and a steam-generating chamber in heat exchange relationship with said heater the combination of a two level tank positioned above the chamber, the upper level of said tank having a lower wall and the lower level of said tank being connected to the vaporizing chamber for supplying water to said chamber, said lower wall of the upper tank level receiving heat from said heater, thermostat means in heat exchange relationship with said lower wall, and means actuated by said thermostat means for indicating the absence of water in the tank above the said lower wall.

References Cited in the file of this patent UNITED STATES PATENTS 2,190,904 Wiggins Feb. 20, 1940 2,440,041 Clark Apr. 20, 1948 2,499,835 Rahos Mar. 7, 1950 2,582,773 Finlayson Jan. 15, 1952 2,619,566 Mahoney Nov. 25, 1952 

